core: fix os.kill(pid, 0) sending CTRL_C on Windows

Root cause: on Windows, signal 0 = CTRL_C_EVENT, so os.kill(pid, 0)
sends Ctrl+C to the process group instead of checking existence.
test_pid_exists_true called os.kill(os.getpid(), 0) which delivered
an asynchronous KeyboardInterrupt during pytest cleanup, causing
exit code 1 despite all 436 tests passing.

Fix: replace os.kill(pid, 0) with psutil.pid_exists(pid) in
AutorunDaemon._pid_exists() for cross-platform correctness.

Reverts: timeout_method="thread", -p no:timeout CI flag, and
KeyboardInterrupt guard in conftest — all were treating symptoms.

Author: ahundt

.github/workflows/ci.yml

@@ -77,16 +77,12 @@ jobs:
         # Safe subset: excludes tests requiring real tmux sessions, running daemon,
         # subprocess spawning, external APIs, or >5s wall-clock time.
         # Coverage threshold (fail_under=60) omitted -- calibrated for full suite.
-        # --timeout=0 on Windows: pytest-timeout thread method sends spurious
-        # KeyboardInterrupt during session teardown on Windows (all tests pass
-        # but exit code is 1). Disable timeout on Windows CI as a workaround.
         working-directory: plugins/autorun
         run: >-
           uv run pytest tests/
           -m "not tmux and not daemon and not subprocess and not e2e and not interactive and not stress and not race and not slow"
           --tb=short -v
           --junitxml=${{ github.workspace }}/test_results_${{ matrix.os }}_py${{ matrix.python-version }}.xml
-          ${{ runner.os == 'Windows' && '-p no:timeout' || '' }}
 
       - name: Publish test results
         # dorny/test-reporter: 1.1k stars, updated 2026, pure Node.js (no Docker).

plugins/autorun/pyproject.toml

@@ -99,7 +99,6 @@ python_files = ["test_*.py"]
 python_classes = ["Test*"]
 python_functions = ["test_*"]
 timeout = 30
-timeout_method = "thread"
 markers = [
     "unit: marks tests as unit tests",
     "integration: marks tests as integration tests",

plugins/autorun/src/autorun/core.py

@@ -1199,12 +1199,14 @@ def __init__(self, app: AutorunApp):
         self._cleanup_registered = False
 
     def _pid_exists(self, pid: int) -> bool:
-        """Check if process with given PID exists."""
-        try:
-            os.kill(pid, 0)
-            return True
-        except OSError:
-            return False
+        """Check if process with given PID exists.
+
+        Uses psutil for cross-platform correctness. On Windows, os.kill(pid, 0)
+        sends CTRL_C_EVENT (signal 0 = CTRL_C_EVENT) instead of checking
+        existence, which causes a spurious KeyboardInterrupt.
+        """
+        import psutil
+        return psutil.pid_exists(pid)
 
     async def handle_client(self, reader: asyncio.StreamReader,
                            writer: asyncio.StreamWriter):

plugins/autorun/tests/conftest.py

@@ -42,14 +42,6 @@ def pytest_configure(config):
     config.addinivalue_line("markers", "e2e: marks end-to-end tests")
     config.addinivalue_line("markers", "serial: marks tests that must run serially")
 
-    # Disable pytest-timeout on Windows: thread-based timeout sends spurious
-    # KeyboardInterrupt during session teardown, causing exit code 1 even
-    # though all tests pass. This overrides pyproject.toml timeout=30.
-    if sys.platform == "win32":
-        try:
-            config.option.timeout = 0
-        except AttributeError:
-            pass
 
 
 # Test file groups for automatic serial/parallel assignment
@@ -386,14 +378,8 @@ def pytest_sessionstart(session):
 
 def pytest_sessionfinish(session, exitstatus):
     """Clean up test sessions and test-spawned daemons after pytest finishes."""
-    try:
-        cleanup_test_sessions()
-        DaemonManager.cleanup()
-    except KeyboardInterrupt:
-        # On Windows, pytest-timeout thread method can send spurious
-        # KeyboardInterrupt during session teardown. Suppress it since
-        # cleanup is best-effort.
-        pass
+    cleanup_test_sessions()
+    DaemonManager.cleanup()
 
 
 @pytest.fixture(scope="session")